About this Abstract |
Meeting |
MS&T23: Materials Science & Technology
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Symposium
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High Entropy Materials: Concentrated Solid Solutions, Intermetallics, Ceramics, Functional Materials and Beyond IV
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Presentation Title |
Predicting Thermodynamic, Thermal, and Mechanical Properties of MoNbTaTi-based Refractory High Entropy Alloys |
Author(s) |
Michael C. Gao, Saro San, Yi Wang, Vishnu Raghuraman, Mike Widom, John Sharon, Yu Zhong |
On-Site Speaker (Planned) |
Yu Zhong |
Abstract Scope |
Refractory high entropy alloys (RHEAs) hold great potentials for ultrahigh temperature applications beyond the current-state-of-the-art nickel-based superalloys. The wide mutual solubility among refractory metal elements in the BCC structure makes it feasible forming single-phase solid solution over large ranges of temperatures and compositions. In this study, modeling and simulations based on density functional theory methods are carried out to predict the thermodynamic, thermal, and mechanical properties of Mo25Nb25Ti25Ta17M8 (M = Al, Cr, Zr, Hf, V, W) RHEAs. In particular, the intrinsic ductility is studied using several popular models, including D parameter (ratio of surface energy over unstable stacking fault energy), χ parameter based on shear instability, ab initio tensile test, ratio of bulk modulus over shear modulus, and Cauchy pressure. Coefficient of thermal expansion and temperature dependent elastic constants are predicted using ab initio molecular dynamics, phonon calculations using quasi harmonic approximation, and Debye model. |